We purchased a Harman Accentra Insert back in 2013. We love it. However, last winter we noticed that the feeder was calling for too many pellets and we'd constantly be dumping the ash tray with partially burned pellets. We've always done thorough cleanings, including the heat probe and having the chimney cleaned regularly. It's like it's calling for too much heat or something. Any suggestions on hot to troubleshoot so we don't waste so many pellets?
Harmen Accentra - partially burned pellets
- Thread starter TimmyC
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Washed-Up
Minister of Fire
Check the holes in the burnpot, make sure they are clear of carbon build up, sometimes they look ok but actually are carboned up, have you cleaned underneath the burnpot, ash fines clog the igniter up, also check the outside air piping and make sure it’s clear as well… sounds like it’s not getting enough air
Thanks for the feedback. Some of the holes in the burnpot are definitely 100% clogged with carbon. To the point where I can't jamn anything through them. How do you suggest cleaning them to have airflow again. Drill with a tiny bit?
Thanks. It happens with multiple brands. We currently burn the very high-end stuff that's the lowest ash producing for our region.
Washed-Up
Minister of Fire
I’ve used a small metal punch on a few occasions…you can use a small drill bit as a last resort just be careful as the igniter isn’t too far underneath inside the burnpot, and I would try by hand first….. definitely unplug the stove if you are going to do this. Also find the right sized but by testing bits into a perfectly clean hole
SidecarFlip
Minister of Fire
I don't know if you can remove it easily as I'm not familiar with a (Harmen) (Harmon) but with my unit the firepot is easily removeable so I have 2. One is soaking in a pail of water while the other is in use. Water will soften the hard carbon and a small wire brush will remove it all (including what is in the holes. I soak mine usually a few days and I use a small welding wire brush to clean it.
I ended up replacing the burnpot entirely, so the holes are totally clean & clear. It's still dumping partially burned pellets in the ash tray in a major way. It's like it's calling for too much heat.
Washed-Up
Minister of Fire
Thermostat is set for room temp. Feed setting is at 3. Room Temp is set is set for Low. Thermostat is set for 70.
I assume you have had the cast iron plates out along with the combustion fan cover off and all is clean back there? When you say "they" cleaned the chimney, did they have all the plates and combustion fan cover off to be able to clean from the square tunnel w/ esp probe in it all the way to the outside termination cap? It there ash built up around the esp in the exhaust tunnel? Did you check the air inlet flapper near the circuit board to be sure it is swinging freely.
A few clooged holes in burn pot will not cause that drastic of a issue on a Harman
A few clooged holes in burn pot will not cause that drastic of a issue on a Harman
Yeah, we regularly take it apart completely to clean, including the combustion fan cover and wipe the ESP probe and vacuum the surrounding area. Have not checked the air inlet flapper.
Washed-Up
Minister of Fire
Good question. I will try that. We did change the settings to stove temp at 70 and it's burning fine now & not calling for too many pellets. I wonder if the thermostat / esb probe is broken?
Washed-Up
Minister of Fire
In stove temp mode what the ESP is "seeing" temperature wise is what drives the feed rate so it would seem that it is performing correctly. I'd lean towards the thermostat being the problem.
Hugh
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Thank you. The thermostat wire is enclosed in a white plastic cable housing that is mounted to the fireplace and mantle. Only about an inch is exposed at the end. Do you think this could be the issue? Perhaps the bricks or mantle are cold?
I once had a situation with my P-43 where the fire was running away and warmed the house up to the mid-80s and was continueing to increase. My first thought was that the computer board had $hit the bed and then noticed that my partner had done some cleaning that lead to the thermostat wire dropping off the mantle to the cold surface of the hearth. Once returned to it's proper location things immediately settled back to normal
So yes if the tip of the temperature sensing wire is too close to a cool surface you'll have a run away stove. It is the tip that contains the element that "senses" the temperature. If you move it out several inches from the mantle it may better reflect the room temperature.Hugh
if the feed it set correctly and the stove is breathing correctly the stove should burn fine and just overheat the room if the room sensor is not sensing correctly. I would experiment in room temp with a thermometer near the room sensing probe and reduce your feed to get a good burn. that will give a rough idea if room sensor is within range
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